Stable lime soap grease



45 fatty acids or vfatty :acid oils may be first saponi- Patented June 21, 1938 UNITED STATES PATENT OFFECE STABLE LIME SOAP GREASE No Drawing. Application June 4, 1936, Serial No. 83,452

4 Claims.

The primary object of the present invention is i the production of a lime soap grease which shall be relatively stable under aging or severe working conditions.

Another object is to provide a method of manufacturing a grease having the foregoing characteristics. I

With the foregoing objects in View, the invention consists in the improved grease and method of manufacture as hereinafter described and more particularly defined by the accompanying claims.

As an example of the method of making a grease of the type forming the subject of the present invention, a mineral oil of 100-200 Saybolt viscosity at 100 F., and :a fatty acid (or lard oil, tallow, etc.) may be mixed, and the mixture heated to about 220 F. with agitation. To the heated mixture there is added lime in amount sufficient to neutralize or substantially neutralize and saponify the fatty :acid, which .for example maybe stearic acid. The heating and agitation is continued until a smooth homogeneous :soapoil mixture results, after which additional oil is gradually added to substantially. equalize the proportions by weight of oil and soap. After gradually cooling the mixture to a temperature of about 150 F. while continuing the agitation, a small amount of water -(1'%2 iis added togeth- -.er with additional mineral oil containingin solution from 0.1%-0.2% by weight of the finished grease .of p'henyl-a'lpha naphthylamine. The total volume of oil :added to the soap is proportioned in accordance with the "desired consistency of the finished grease. If more convenient, the

fled with lime to produce soap before any of the -.oil is added.

ilhe discovery forming the basis of the invention is that the very small amount of phenylstituents of the grease.

alpha-naphthylamine employed is efiective in stabilizing the grease, apparently'as a result of some strong stabilizing effect in holding the water in an emulsified dispersion even under severe working conditions. Another advantageous prop- 5 erty of the phenyl-alpha-naphthylamine is that by its use no particular care has to be taken to completely saponify the fatty acid, such as is usually necessary in producing this type of grease; since phenyl-alpha--naphthlyamine present in the amount indicated seemingly inhibits any unstabilizing effect of as much as 0.3% to 0.4% unsaponified fatty acid in the grease.

The invention having been thus described,' w'hat .is claimed as new is:

1. A grease comprising a semi-solid emulsion of heavy mineral oil, fatty acid-lime soap, 1-2% by weight of water, and 0.1'-%-0:2% phenyl-alpha naphthylamine as a stabilizing agent for the emulsion. adapted to prevent separation of its 6 constituents.

2. A method of making grease comprising heating and agitating a mixture of fatty acid-lime soap and heavy mineral oil at a temperature of about-220 F. to produce .a smooth homogeneous base mixture, cooling the mixture to about 150 F. and agitating while gradually admixing therewith about 1-2% by weight of water, 0.1'-%-0.2% of pheny'l-alpha-naphthylamine as a stabilizing agent adapted to prevent separation of the constituents of the grease, and suflicient additional heavy oil to thin the grease to the desired con sistency.

3. A grease composition comprising a homogeneous mixture of a lime soap,a mineral oil, and -a relatively small proportion'of phenyl-alpha- I naphthylamine suflic'ient to stabilize the grease and maintain the same homogeneous under storage and use conditions.

4. The process of stabilizing greases containing m a lime soap and mineral oil against separation of their constituents under storage and use conditions, which comprises intimately incorporating in the grease a relatively small proportion of phenyl-alpha-naphthylamine as a stabilizing agent adapted to prevent separation at the con- 

